From a4dba970bb17463ca9a2151fc52746915a27eb32 Mon Sep 17 00:00:00 2001
From: Quintin Willison <q@qwuk.net>
Date: Tue, 28 Feb 2023 09:26:01 +0000
Subject: [PATCH 1/3] Add mode input and URL base output.

---
 action.yml   | 12 ++++++++++++
 src/index.ts |  9 ++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/action.yml b/action.yml
index 50876f0..4593d68 100644
--- a/action.yml
+++ b/action.yml
@@ -21,3 +21,15 @@ inputs:
       If not supplied or supplied as an empty string then the artifacts are uploaded to S3 at root for this deployment context.
     required: false
     default: ''
+  mode:
+    description: |
+      Specify `"preempt"` in order use this action before content build in order to output the URL base.
+    required: false
+outputs:
+  url-base:
+    description: |
+      The URL base. For example:
+
+          https://sdk.ably.com/builds/ably/ably-flutter/pull/307/dartdoc/
+
+      When used in the Flutter SDK repository, with `artifactName` as `"dartdoc"`.
diff --git a/src/index.ts b/src/index.ts
index f48fdb6..c8ebff3 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -89,6 +89,13 @@ if (artifactName.length > 0) {
 core.debug(`S3 Key Prefix: ${s3KeyPrefix}`);
 core.debug(`GitHub Environment Name: ${githubEnvironmentName}`);
 
+const urlBase = `https://${s3BucketName}/${s3KeyPrefix}/`;
+const runMode = core.getInput('mode');
+if (runMode === 'preempt') {
+  core.setOutput('url-base', urlBase);
+  process.exit(0);
+}
+
 const s3ClientConfig: S3ClientConfig = {
     // RegionInputConfig
     region: 'eu-west-2',
@@ -163,7 +170,7 @@ const run = async () => {
                 ContentType: lookup(file) || 'application/octet-stream',
             });
         }));
-        await setDeploymentStatus(deploymentId, 'success', `https://${s3BucketName}/${s3KeyPrefix}/`);
+        await setDeploymentStatus(deploymentId, 'success', urlBase);
     } catch (err) {
         await setDeploymentStatus(deploymentId, 'failure');
         throw err;

From 255ccd1f7066b2b7adea32016efed5b384b694fb Mon Sep 17 00:00:00 2001
From: Quintin Willison <q@qwuk.net>
Date: Tue, 28 Feb 2023 09:33:26 +0000
Subject: [PATCH 2/3] Document the URL base output as well as the mode input.

---
 README.md | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/README.md b/README.md
index 585c778..06e8b6a 100644
--- a/README.md
+++ b/README.md
@@ -4,6 +4,8 @@ This action automates the deployment of generated artifacts to our Ably SDK team
 
 ## Usage
 
+### Usage After Artifact Generation
+
 See [action.yml](action.yml) for explanations of each input.
 
 ```yaml
@@ -31,6 +33,19 @@ In the above example, `<REPO-NAME>` should be the Ably repository name (e.g. `ab
 
 If `artifactName` is not specified, or specified as an empty string, then artifacts are pushed to the root of the upload context (i.e. dropping `/${artifactName}` from the URL structures outlined above).
 
+### Usage Before Artifact Generation
+
+There are times when the URL base on `sdk.ably.com` needs to be known ahead of artifact build.
+
+This action has an input called `mode` which can be set to `"preempt"` in order to obtain this information up front.
+
+If the preempt mode is requested then nothing will be uploaded to S3, however the action will emit an output called `url-base`,
+containing the URL base as a string value. For example:
+
+    https://sdk.ably.com/builds/ably/ably-flutter/pull/307/dartdoc/
+
+When used in the Flutter SDK repository, with `artifactName` as `"dartdoc"`.
+
 ## Permissions
 
 ### AWS

From b7796472cc2455a321afb9e6ac7b359a5ee52776 Mon Sep 17 00:00:00 2001
From: Quintin Willison <q@qwuk.net>
Date: Tue, 28 Feb 2023 09:42:32 +0000
Subject: [PATCH 3/3] Emit the URL base output regardless of mode.

Feels safer as contract in action.yml strongly suggests the output will always be present.
---
 src/index.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/index.ts b/src/index.ts
index c8ebff3..f219262 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -90,9 +90,9 @@ core.debug(`S3 Key Prefix: ${s3KeyPrefix}`);
 core.debug(`GitHub Environment Name: ${githubEnvironmentName}`);
 
 const urlBase = `https://${s3BucketName}/${s3KeyPrefix}/`;
+core.setOutput('url-base', urlBase);
 const runMode = core.getInput('mode');
 if (runMode === 'preempt') {
-  core.setOutput('url-base', urlBase);
   process.exit(0);
 }